Explain principle of electron microscopy : Biology Blog
Principle of electron microscopy Around 1931-32, two German scientists, Knoll and Ruska invented transmission electron microscopy and developed a transmission the electron microscope (TEM) around 1940. Principle - A strong beam of electrons discharged from tungsten filaments after supplying them with high voltage electronic current, pass through a vacuum and refocussed electromagnets. Radiation (wavelength 0.05 angstrom) is produced from it which is utilized as a source of illumination to the objects. An image is formed when electrons strike on a fluorescent screen or on a photographic film. Several hundred thousand times magnifications and resolution of about 5 angstroms can be achieved by TEM. The compound of a transmission electron microscope - Electrogun - it is located on the top of the microscope. It works as a source of electrons. It con...